Not Applicable.
Not Applicable.
1. Field of the Invention
This invention relates to an electronically-actuated display array, specifically, to such an array that uses different combinations of differently-shaped segments to display arithmetic operation symbols.
2. Prior Art
Numerous liquid-crystal displays and other electronically-actuated displays display a multiplication symbol (xc3x97) and at least one other symbol signifying one of the arithmetic operations of addition (+), subtraction (xe2x88x92), and division (÷ or occasionally /). Many of these displays attempt to reduce cost and/or increase visual clarity by using an array of differently-shaped segments to display these symbols. The following patents and products are illustrative of this prior art.
RadioShack Corporation has marketed under the trademark xe2x80x9cTalking Math Calculatorxe2x80x9d a handheld device for teaching arithmetic skills. This device electronically displays two-operand arithmetic problems involving a selected one of the four basic arithmetic operations (e.g., 6 [divided by] 3). The device displays the symbols for these operations (+, xe2x88x92, xc3x97, ÷), one symbol at a time, in separate, non-overlapping locations in its liquid crystal display (LCD). As a result, although these symbols are legible, they are not located in the same location or where the operator would normally expect to see them, and they are disproportionately smaller than the displayed numbers to which they relate. Consequently, they are not readily noticed or easily viewed. For instance, although the two operands of an addition problem are displayed in a horizontal format (i.e., with the second operand to the right of the first operand), the addition symbol (+) is not located between the two operands where the user would expect to see it, but rather substantially above the operands. Nor is the symbol displayed with dimensions that even approach being proportional to those of the displayed digits of the operands. As a result, the fact that an addition problem is being displayed is not readily apparent. The inadequacies of the LCD result in large part from its inability to display all four arithmetic symbols in the same appropriate location (i.e., between the two operands) and, therefore, from its need to use four separate locations, which in turn results in compromises in the sizing and location of the symbols.
Texas Instruments, Incorporated, has marketed, under the trademark xe2x80x9cMath . . . To Go!xe2x80x9d, a handheld device that teaches basic arithmetic. This device can display two-operand arithmetic problems, including a representation of any one of the above-listed four basic arithmetic operator symbols. But its representation of a multiplication symbol consists solely of four diagonally-oriented lines pointing toward a vacant center and, therefore, does not closely simulate a normal multiplication symbol. This is especially undesirable in view of the fact that multiplication probably is practiced more than any of the other three basic arithmetic operations. Moreover, the device""s addition symbol can be confused with its division symbol.
ExploraToy, under the trademark xe2x80x9cmath whizxe2x80x9d, has also marketed a handheld device that teaches basic arithmetic. It too displays arithmetic problems, including a representation of any one of the four basic arithmetic operator symbols. And its representation of a multiplication symbol also consists solely of four diagonally-oriented lines pointing toward a vacant center and, therefore, does not closely simulate a normal multiplication symbol.
U.S. Pat. No. 4,040,048, issued Aug. 2, 1977 to Lien, discloses a light-emitting-diode display array that displays, one at a time, symbolic representations of the four basic arithmetic operations, using appropriate combinations of seven segments (horizontal, V-shaped, and vertical). The multiplication symbol, however, has a vacant center which detracts substantially from its clarity and esthetic appearance. Moreover, the vertical arms of the addition symbol have confusing gaps, two of which are caused by the fact that V-shaped segments are used for the multiplication symbol.
U.S. Pat. No. 4,340,374, issued Jul. 20, 1982 to Culley, illustrates in FIG. 2 in connection with disclosed electronic learning aids another similar array of component segments for displaying, one symbol at a time, representations of the addition symbol, the subtraction symbol, the multiplication symbol, and the division symbol. To represent the multiplication symbol, this array uses four straight diagonally-oriented segments instead of two V-shaped segments. Again, the effectiveness of the multiplication symbol suffers substantially from a vacant center.
U.S. Pat. No. 5,135,398, issued Aug. 4, 1992 to Thornton et al., and U.S. Pat. No. 5,137,457 issued Aug. 11, 1992 to Howard et al., illustrate in connection with disclosed electronic teaching devices an 11-segment array for displaying the four arithmetic operation symbols. The array uses a central square segment; two horizontal rectangular segments, one directly left and the other directly right of the central segment; four almost-square segments, two directly above and two directly below the central segment; and four diagonally-oriented segments arranged symmetrically around the central segment. Despite the importance of the multiplication symbol, the resulting representation of that symbol appears to have four triangular cavities around its center when compared to a normal multiplication symbol and, therefore, is significantly less effective than it would otherwise be.
Thus, all these prior-art devices either (1) display a multiplication symbol whose central portion is seriously flawed by a design that attempts to accommodate other arithmetic operation symbols in the same location; or (2) display (a) some of the four basic arithmetic operator symbols in locations where the operator does not expect to see them and (b) all the symbols in smaller than optimal proportions. In the first instance, especially in the case of young users, the often very important multiplication symbol is confusing, not quickly recognizable and/or eventually fatiguing to the user. In the second instance, the disproportionately-small and inappropriately-located symbols tend to be less noticeable and to make the device more time-consuming. In both instances, the device in question is less convenient and pleasing to use and, therefore, less likely to be used. Moreover, in attempting to commit to memory a basic arithmetic equation (math fact), such as 7xc3x978=56, a student will sometimes find it helpful to form a mental visual image of the math fact. However, if a device presents the problem (7xc3x978) and the math fact (7xc3x978=56) with a visually distorted or disproportionately-small and inappropriately-located arithmetic operator (here, the multiplication symbol), the device does not effectively reinforce the student""s mental image of the math fact.
In view of the above, several objects of the invention are as follows: To provide an improved arithmetic display array; To provide an electronically actuated visual display array that can economically display, one at time, the symbols of all four of the basic arithmetic operations and that substantially eliminates all of the above-described disadvantages associated with prior-art devices; To provide alternative types of an electronically actuated visual display array that, even within the physically-limited confines of an inexpensive portable device, can clearly and relatively fully display, one symbol at a time and in the same appropriate location, essentially true representations of (a) a multiplication symbol approximating xe2x80x9cxc3x97xe2x80x9d and (b) one or more other of the following: an addition symbol approximating xe2x80x9c+xe2x80x9d, a subtraction symbol approximating xe2x80x9cxe2x88x92xe2x80x9d, and a division symbol approximating xe2x80x9c÷. xe2x80x9d
A further object is to provide display arrays which are like all those described above and which have the additional capability of displaying all segments used in the different arithmetic operation symbols simultaneously as a composite symbol.
Still further objects and advantages will become apparent from consideration of the ensuing description and drawings.
The present invention provides an economical, multi-segment, electronically-actuated display array for visually displaying one arithmetic operation symbol at a time. Specifically, it displays (a) a multiplication symbol configured approximately like xe2x80x9cxc3x97xe2x80x9d and (b) one or more of (1) an addition symbol configured approximately like xe2x80x9c+xe2x80x9d, (2) a subtraction symbol configured approximately like xe2x80x9cxe2x88x92xe2x80x9d, and (3) a division symbol configured approximately like xe2x80x9c÷xe2x80x9d. A novel central segment or central group of two to five adjacent segments (central xe2x80x9csegment groupxe2x80x9d) of the display array displays a central portion of the multiplication symbol and of the other displayable arithmetic operation symbol or symbols. This central portion of the symbols includes, at least, essentially the entire intersection of (a) the multiplication symbol and (b) a horizontal bar constituting the entire subtraction symbol, the horizontal portion of the addition symbol, and/or the vertically-centered portion of the division symbol, depending upon which of these other symbols can also be displayed. A novel feature of the central segment or central segment group is that while it is used to display a central portion of each arithmetic operation symbol displayable by the display array, its maximum horizontal dimension significantly exceeds (a) the maximum vertical dimension of the just-referenced horizontal bar and (b) if the addition symbol is displayable by the display array, the maximum horizontal dimension of segments or segment groups used solely to display vertical portions of the addition symbol. This feature results in a more filled-out and true representation of the multiplication symbol without substantially compromising the representation of other arithmetic symbols. The preferred embodiment has a 13-segment, LCD array that can display all four arithmetic operation symbols individually or all their component segments as a composite symbol, and the array""s novel central segment is hexagonal and has a V-shaped indentation pointing horizontally into each of its left and right extremities.